FIG. 1 is a diagram illustrating a typical cellular communication system including a relay station.
In FIG. 1, using fixed relay stations boosts coverage in cellular networks. This is a low-cost and low-complexity solution to meet requirements of high data rate communications even in highly attenuated propagation environments such as cell-edges. This fact can be applied to all communication system using a fixed relay station.
For better performance, applying MIMO technology to base station and mobile station is under progress, and when the MIMO technology is applied to the fixed relay station, better performance can be achieved. Multi-user transmission is the most important part in the MIMO technology.
However, the current research on the fixed relay station has focused on the single user transmission and multiuser transmission using the MIMO technology is not studied enough.